1. Field of the Invention
The present invention relates to a cathode ray tube (CRT), and more particularly, to an inner shield for a CRT for preventing terrestrial magnetism from affecting the electron beam emitted from an electron gun.
2. Description of the Related Art
Referring to FIG. 1, a conventional CRT includes a panel 10 having a fluorescent layer 11 located at its inner surface, a shadow mask frame assembly 12 spaced a predetermined distance from the fluorescent layer 11, a funnel 20 sealed to the panel 10, and an electron gun (not shown) installed in a neck portion 21 of the funnel 20.
In the CRT having such a configuration, the electron beam emitted from the electron gun is selectively deflected by a deflection yoke (not shown) according to an image signal to then land on the fluorescent layer 11 and excite the fluorescent layer 11.
However, electron beams emitted from the electron gun may not land precisely on a predetermined portion of the fluorescent layer because of the effect of terrestrial magnetism, according to the place where the CRT is installed. Thus, the proceeding path of the electron beam is surrounded by an inner shield 30 made of metal for shielding from terrestrial magnetism.
The inner shield 30 is constituted by first and second side walls 31a and 32a. The first and second side walls 31a and 32a form the inner shield 30 such that first half-side walls 31b and 31b' and second half-side walls 32b and 32b', extending inward from their both ends, are coupled to each other. In other words, as shown in FIG. 2, bending hooks 33 and 34 are located at upper of the first and second half-side walls 31b (31b') and 32b (32b'), respectively. The bending hooks 33 and 34 are coupled to the upper ends of the corresponding half-side walls so that the first and second side walls 31a and 32a are coupled to each other. The bending hooks 33 and 34 are located such that extension pieces at upper edges of the half-side walls are bent during assembly.
However, the connection strength of the bending hooks 33 and 34 with respect to the first and second side walls 31a and 32a of the inner shield 30 is relatively weak. Also, since the bending hooks 33 and 34 are located and then bent for assembly, assembly processes are complicated. Further, the first half-side wall 31b or 31b' and the second half-side wall 32b or 32b' tend to slip relative to each other due to vibrations, which causes foreign matter to be generated due to abrasion.